Miami — The outward calm here is deceptive. While life goes on much as usual in most parts of Miami, some long-smoldering issues in the black community may have been fanned by the violence in black neighborhoods here last week.
Scattered looting, burning, and assaults followed the not-guilty verdict by a jury with no blacks on it in the case of a Hispanic Miami police officer who shot and killed a black youth in 1982. The officer said he shot in self-defense when the youth reached for a gun.
The smoldering issues are:
* The repeated exclusion of blacks from juries trying police officers for the killings of blacks.
* A perception that police use too much force in making arrests, including those made during sweeps last week. Some blacks, however, praised the latest police show of force for preventing worse violence.
Standing with a visitor atop a dirt knoll in a vacant lot in a black section of Miami's Coconut Grove section, Rodney Thomas watched shotgun-carrying, helmeted police in six unmarked cars suddenly sweep into his neighborhood one night last week and make several arrests. Some youths had been throwing rocks and had set a sofa ablaze on a street.
''Black people in the city of Miami don't get justice at all,'' he said. ''We have all-white juries. The only way to retaliate is violence.''
Police use excessive force ''more than sometimes,'' he charged. Mr. Thomas, a 25-year-old black security guard, complained bitterly after police, with long nightsticks and other weapons drawn, arrested some of the youths. He said he had applied to become a police officer but had changed his mind. ''I don't want to treat nobody this way,'' he said.
The American Civil Liberties Union is investigating allegations of violation of constitutional rights by police during the sweeping arrests. Many of those arrested claim to have been simply bystanders.
In the Liberty City section of Miami, where a 1980 riot resulted in some 18 deaths, black mechanic Lawrence Quarterman said the jury's acquittal shouts a message to blacks: ''A white cop can kill a black man any time and get away with it.''
But in the Overtown section of Miami, the black neighborhood where the youth, Neville Johnson Jr., was shot by the officer just acquitted, police at one corner were chatting in a friendly, relaxed way with area youth Friday evening when black social worker Georgie Ayers and a visitor arrived.
Under the glare of a corner streetlight, young blacks walked by or rode by quietly on bicycles. Others drive by in cars with music blaring. A woman pushed a stroller along the sidewalk and the baby in it was jangling a set of keys.
Asked about the verdict, one black youth said it was ''fair.'' Then he did a couple of breakdance steps in the middle of the street. Another youth said the verdict ''wasn't surprising after they went through his (victim's) criminal record.'' But, he added, the fact that there were no black jurors ''was not good.''
One of the white police officers at the corner, wearing a bulletproof vest and a green bag with a gas mask in it on his belt, said of the officer's killing of the youth: ''Mistakes are made.'' The black officer with him said: ''As a police officer you don't intend to kill anyone.''
''We're human; we're not supermen,'' added a third officer, leaning against Mrs. Ayers's car.
Later that evening, at another police barricade, an officer who normally works on organized crime said officers have to ''make a decision (on when to shoot) in two seconds.''
In 1980, police were caught off guard by the explosion of violence and killing that followed the acquittal by an all-white jury of police officers who apprehended a black man after a high-speed chase. The officers clubbed him to death in what they said was an ensuing struggle.
Instead of moving into the rioting neighborhoods in 1980, in many cases the police and Florida National Guard troops simply circled them and waited for the violence to subside. This time they moved in quickly in large numbers, making several hundred arrests in a two-day period. Since 1982, a number of blacks, some just recently, have been moved into high-command positions on the police forces here.
But the scene during the Coconut Grove arrests shows that a wide gap still exists between police and blacks.
When Mrs. Ayers arrived on the scene, there was only one police car there. The white officers asked her for help as a member of the crisis response team - community leaders trying to help keep the calm.
She walked past the still-burning sofa in the street to the group of youths on the corner. She scolded them and told them to go home because the police were coming and making arrests. They lingered on, however.
A few minutes later, the other police cars arrived and within minutes a chase ensued.
Several youths fled to a nearby home. Gloria Mattison, the mother of one of the youths arrested, said police rushed in with weapons drawn and ''grabbed my son and threw him down.''
''It's like the storm troopers,'' said Harry Mattison, whose brother was arrested. He said he might have used a gun against the police if he had been in the home when they arrived like that. He said he had applied to be a police officer, too, but had decided not to because of previous behavior by police.
''I was at one time pro-cop; I'm anti-cop now,'' he said. In an interview after his release from jail pending a court hearing, Michael Mattison gave his version of the arrest: An officer barged in, and, using profanity and racial slurs, ''he snatched me; I hit him. We tussled on the ground.''
Other officers arrived, and the young black was subdued. Asked if anyone had read him his rights, Michael said no.
Overall, police handled the violence in Miami well, said Mrs. Ayers. But chasing rock-throwers into a home with guns drawn was ''uncalled for,'' she said. ''They wouldn't do that in an affluent home,'' she said.